Postharvest Auxin and Methyl Jasmonate Effect on Anthocyanin Biosynthesis in Red Raspberry (Rubus idaeus L.)

摘要

Fruit color is fundamental for consumer acceptance. There is evidence that plant growth regulators, such as indole-3-acetic acid (IAA) and methyl jasmonate (MJ), are related to the inhibition or increase of flavonoids in red raspberries (Rubus idaeus L.). We evaluated the effect of IAA and MJ treatment in the anthocyanin content in red raspberries cv. Autumn Bliss. Ethylene, IAA, and MJ levels were determined, as well as the relative transcript levels of anthocyanidin synthase (ANS, leucocyanidin oxygenase; EC 1.14.11.19), dihydroflavonol 4-reductase (DFR; dihydrokaempferol 4-reductase; EC 1.1.1.219), and MYB10, a transcriptional regulator of the anthocyanin pathway in raspberries were also determined. The MJ-treated fruits developed an intense red color 2 days after harvest (DAH) and prior to anthocyanin accumulation, which was associated with an increase in the relative expressions of MYB10, ANS, and DFR. Five DAH, the anthocyanin and the total phenolic contents were lower in the IAA-treated fruit than the control group. These effects were related to the inhibition of MYB10 and ANS transcription and correlated to changes in IAA and MJ contents in the fruit flesh. These results suggest that anthocyanin metabolism is regulated by the interplay of multiple hormonal signs, including IAA and MJ, affecting specific steps during raspberry maturation, such as transcription factors of the anthocyanin pathway.